Why Does Windows Use So Much Disk Space?

Ever wondered just what’s hiding in the various system directories that make up Windows, or why an operating system needs to take up quite so much room? A post at the Engineering Windows 7 blog reveals some of the secrets of Windows’ internal structure (including how some files get counted twice if you try and do a right-click directory size measurement). It also explains why deleting the apparently space-hogging WinSxS directory is a bad idea, which is a useful addition to our existing collection of Vista performance-tweaking myths.